An Overview of Hubble’s Secondary Mirror Moves
This table gives the dates, times, and movement in microns of the HST Secondary Mirror adjustments necessary to counter the long-term shrinkage of the telescope and maintain overall focus.
All Secondary Mirror movements are in pure despace (axial motion producing a focus change). A positive value represents a movement of the Secondary away from the Primary. 1 micron of Secondary Mirror despace induces 6.1 nanometers of rms wavefront error in focus at the SIs.
| Day of Year | Time (UT) |
Secondary Move |
|---|---|---|
| 29 Jun 1994 | 17:36 UT | +5.0 |
| 15 Jan 1995 | 23:40 UT | +5.0 |
| 28 Aug 1995 | 15:16 UT | +6.5 |
| 14 Mar 1996 | 18:47 UT | +6.0 |
| 30 Oct 1996 | 17:40 UT | +5.0 |
| 18 Mar 1997 | 22:55 UT | -2.4 |
| 12 Jan 1998 (NIC3 campaign 1) |
01:15 UT | +21.0 |
| 01 Feb 1998 | 16:40 UT | -18.6 |
| 04 Jun 1998 (NIC3 campaign 2) |
01:01 UT | +16.6 |
| 28 Jun 1998 | 17:26 UT | -15.2 |
| 15 Sep 1999 | 15:40 UT | +3.0 |
| 09 Jan 2000 | 17:42 UT | +4.2 |
| 15 Jun 2000 | 19:38 UT | +3.6 |
| 02 Dec 2002 | 20:50 UT | +3.6 |
| 22 Dec 2004 | 23:12 UT | +4.16 |
| 31 Jul 2006 | 14:35 UT | +5.34 |
| 20 Jul 2009 | 09:35 UT | +2.97 |
| 24 Jan 2013 | 17:58 UT | +3.60 |
| 11 Nov 2013 | 17:41 UT | +2.97 |
| 5 Feb 2015 | 17:26 UT | +1.78 |